regarding my sharpening capabilities ... well, I'm coming from the knife world. I started getting into Japanes Knives some three years ago. Meanwhile, I have some nice handmade kitchen knives and also some collectibles. With the knives came the stones. Right now I own some ordinary combos, some DMT's, a set of Naniwa Choseras (400,1000,3000,5000), a Naniwa Super 10'000, and two japanese naturals, one Aoto and one Awaseto. Plus a bunch of strops (hanging, backed) partially pasted (CrOx). While I'm still far away from any japanese sharpening professional I manage to get a consistently sharp edge on any of my knives, regardless of the steel type, far beyound anything you can buy in shops. Of course this puts me nowhere close to be able to sharpen a razor on my first attempt. Yet, I think that this gave me some experienece how steel behaves, how to "listen" to stones, how to feel the drag, ... ya know what I mean.
So, recently I got into straight razors after reading about them on the net every once in a while. I have to adimit that I was addicted right away (I guess I'm telling no news here ...
). I got my frist razor three months ago (a nice Revisor) and today there are already 8 pieces in my bathroom shelf. Some of them I got with the primary intention to use them as sharpening training objects. So by now I would say that I did about 25 complete sharpening sessions, experimenting with different stone combinations and improving my honing skills. I found that I get the best results with the Naniwa setup. First the Choseras 1000,3000,5000 (did I mention that I just LOVE these stones, but that's another story) then finishing off on the SS10'000, on to the paste strop and then the leather. With this I'm able to get a consistent HHT-3 after stropping and the shaving goes well (but I never had one from a "Master Sharpener" to compare). I also gave the Japanese naturals some tries but somehow did not find my way with them yet. And now come these two Cotis ....
So much seems clear: Judging by the slurry both are definitely Coticules. Booth of them raise a very nice and fine slurry that looks just the way it is shown in any videos/pictures I've seen so far.
Yesterday I gave both of them a try with a training knife which I dulled befor I started. I tried to stick (or at least lean to ) the updated diluticot method. As a general impression I can say that the grise seems to be a lot harder and has much less abrasive properties than the reddish one. I did 30 half strokes with milky slurry and some pressure with my index finger and the discoloration from shaved steel was just barely visible. The more I diluted the more I had the feeling of a almos glass-like surface. Under the microscope the edge looked quite nice and homogeneous but even after using a pasted strop and many strokes on leather I was not able to get a sucessfull HHT (althoug, after the first slurry session I could shave my arm hair). Since this was the second sharpening session I tried to use the knive to shave this morning anyway. I did some passess with the grain on my cheek and it shaved. It was far from great but it was not absolutely miserable either. Not so good that I would try to shave against the grain, though ... i don't know, but somehow this rock really semms to has some secrets to it.
The red stone was easyer to work with. After the first set of half strokes I had a clearly visible discoloration and could shave my arm hair. It seemed softer and gave me a bit more feedback in my hand. At the end, after stropping I managed to pop some hairs with a bit of goodwill. To bad I could not try that edge for a shave.
Regardless of these observations bear in mind that I am unexperienced with Cotis and therefore, the human factor may play a signifacant role here too.
About the backsides ... If you look what Murray Carter can do to a knive with a construction brick and a piece of cardboard, then question Is not really if an object can sharpen a knive but if it was INTENDED to do so. Regarding the brown backings I doubt that this is the case. The abrasive capabilities are mediocre at best and it will raise no significant slurry. I am also not sure if it is of synthetic origin. It looks so much different than any synthetics I have seen. It has pores of irregular size and the color is varying too. I would not bet anything on that but it really seems to be something like tuffstone.
I'm affraid that there is not more information from the shop where I got them. The storage box I pulled them from was nothing but exactly that, a plain old cardboard storage box with all sort of wheatstones in it (all but two completey unspectacular). The Cotis were not individually packaged. So no trace there ...
So it seems like a interesting puzzle to solve. Bart, if you find the time to ask back in Belgium that would be great! If you're interested I may even think about sending them out to you after getting some more tries on them myself. I will be gone on business trip for two weeks so I will not have the time to play with them until May. But of course I will continue to be in the Cafeteria and see if any more info pops up.
Have a good one all